Appendix B - Technical Specification for Plain & Reinforced concrete ...

VISAKH MARKETING INSTALLATION REISTEMENT PROJECT-BLACK OIL TERMINAL Doc No: 254625-300-SP-CIV-002

Rev: B

Page 1 of 24

TECHNICAL SPECIFICATION FOR PLAIN AND REINFORCED CEMENT CONCRETE WORKS

Mott MacDonald Consultants (India) Pvt. Ltd.

Hindustan Petroleum Corporation Ltd

Kothari House, CTS No. 185

Visakha Dispatch Station

Off Andheri - Kurla Road

VR-ATP Area, Naval Base Post

Andheri (East)

Visakhapatnam - 530 014

Mumbai 400 059

Andhra Pradesh

P:\Andheri\IndiaProject\254625 HPCL- Black Oil Terminal\02 Civil\Documents\Deliverables\Documents\Latest\SPECIFICATIONS\REV B\Spec for Plain and Reinforced Cement Concrete.doc

VISAKH MARKETING INSTALLATION REISTEMENT PROJECT-BLACK OIL TERMINAL Doc No: 254625-300-SP-CIV-002 List of Contents

Rev: B

Page 3 of 24 Page No

1

Scope

6

2

Applicable Codes

6

3

Materials

7

3.1

Cement

7

3.2

Aggregates

7

3.3

Water

7

3.4

Brick Aggregates

7

3.5

Reinforcement

8

3.6

Water Stoppers

8

3.7

Jointing/Sealing Materials

8

3.8

Admixtures

8

4

Storage of Materials

8

4.1

Cement

8

4.2

Aggregates

8

4.3

Reinforcing Steel

9

4.4

Miscellaneous

9

5

Grades of Concrete

6

Type of Concrete Mix

10

6.1

General

10

6.2

Nominal Mix Concrete

10

6.3

Design Mix Concrete

10

Concrete Mix Proportioning

11

7.1

Maximum Density

11

7.2

Free Water Cement Ratio

11

7.3

Consistency

12

7.4

Workability

12

7.5

Durability

12

7

9

8

Batching

13

9

Concrete Mixing

14

9.1

14

General



9.2 10

Rev: B

Page 4 of 24

Additives

14

Transportation, Placing and Compaction

14

10.1

14 15 15 15 15

General 10.1.1 Vibrators 10.1.2 Transportation 10.1.3 Placing and Compaction 10.1.4 Items Embedded in Concrete

11

Construction Joints

16

12

Expansion Joints / Isolation Joint

16

13

Protection of Freshly Laid Concrete

16

14

Curing

16

15

Field Tests

17

15.1

Workability

17

15.2

Work Tests

18

15.3

Standard Deviation

18

15.4

Acceptance Criteria

18

16

17

18

19

20

Finishing of Concrete

19

16.1

19

General

Form Work

19

17.1

General

19

17.2

Cleaning and Treatment of Formwork

19

17.3

Chamfers and Fillets

19

17.4

Reuse of forms

20

17.5

Removal of Forms/Stripping Time

20

Exposed / Architectural Concrete Work

21

18.1

21

Form Work

Reinforcement

21

19.1

Straightening, Cutting and Bending

21

19.2

Placing and Fixing

21

19.3

Splicing/Overlapping

22

19.4

Tolerance to Cover

22

Damp Proof Course (DPC)

22



Rev: B

Page 5 of 24

21

Grouting

22

22

Clean Up

23

23

Payment

23

23.1

Plain and Reinforced Concrete

23

23.2

Reinforcement

24

23.3

Expansion/Isolation Joints

24


VISAKH MARKETING INSTALLATION REISTEMENT PROJECT-BLACK OIL TERMINAL Doc No: 254625-300-SP-CIV-002 1

Rev: B

Page 6 of 24

Scope This specification establishes the minimum requirements of materials, quality, batching, mix proportioning, transporting, placing, protecting, curing, repairing, finishing & testing etc. of all types of cast-in-situ and precast concrete used in foundations, underground and aboveground structures, floors, pavements etc. Any special requirements as shown or noted on the drawings shall supersede over the provisions of this specifications.

2

Applicable Codes Apart from this specification, construction of plain and reinforced concrete works shall be in accordance with the Indian Standard Code of Practice for "Plain and Reinforced Concrete" IS:456 and other relevant codes mentioned therein. The following Indian Standards including all amendments and revisions shall be considered as part of this specification. IS: 269 : 1989 IS: 383 : 1970

Specification for Ordinary. Rapid hardening & Low heat Portland cement Specification for Coarse & fine aggregates from natural sources for concrete IS: 432 : 1982 Specification for mild steel and (Part I & II) medium tensile steel bars and hard drawn steel wire for concrete reinforcement. IS: 455 : 1989 Specification for Portland Blast Furnace Slag cement. IS: 456 : 2000 Code of Practice for Plain and Reinforced Concrete. IS: 516 : 1959 Methods of Tests for Strength of Concrete. IS: 650 : 1991 Specification for standard sand for testing of cement. IS:1139 : 1966 Specification for hot rolled mild steel and medium tensile steel deformed bars for concrete reinforcement. IS:1199 : 1959 Methods of Sampling and Analysis of Concrete. IS:1200 : 1992 Methods of measurement of building works. IS:1489 : 1991 Specification for Portland Pozzolona Cement. IS:1566 : 1982 Specification for plain hard drawn steel wire fabric for concrete reinforcement. IS:1786 : 1985 Specification for High Strength Deformed Steel Bars and Wires for Concrete Reinforcement. IS:1791 : 1985 Specification for Batch Type Concrete Mixers. IS: 2386 : Methods of Test for Aggregates for Concrete: Part 3, Specific gravity, 1963 density, voids, absorption and bulking. IS: 2396(I) : Flakiness index of aggregates 1988 IS:2502 : 1963 Code of Practice for Bending and Fixing of Bars for Concrete Reinforcement. IS:2505 : 1992 Specification for concrete vibrator immersion type. IS:2645 : 2003 Specification for integral cement water proofing material. IS:2750 : 1964 Specification for steel scaffolding IS:2751 : 1979 IS:2772 : 1982 IS:3696 : 1987 IS:4014 : 1967 IS:4031 : 1988

Recommended Practice for Welding of Mild Steel Plain and Deformed Bars for Reinforced Concrete Construction. Specification for portable swing weigh-batchers for concrete Safety code for scaffolding and ladders Code of Practice for steel tubular (Part I & II) Scaffolding Method of physical tests for hydraulic cement



Rev: B

Page 7 of 24

IS:4926 : 2003 IS:4990 : 1993 IS: 7861 Part I : 1975 Part II : 1981 IS:9013 : 1978

Ready Mixed Concrete Specification for plywood for concrete shuttering work Code of Practice for Extreme Weather Concreting. Recommended Practice for Hot Weather Concreting. Recommended Practice for Cold Weather Concreting. Methods of Making, Curing and Determining Compressive Strength of Accelerated Cured Concrete Test Specimens. IS:9103 : 1999 Specification for Admixtures for Concrete. IS:9417 : 1989 Recommendation for Welding Cold Worked Steel Bars for Reinforced Concrete Construction. IS:10262 : Recommended Guidelines for Concrete Mix Design. 1982 IS:14687 : Guidelines for Formwork for Concrete Structures. 1999

3

Materials

3.1

Cement Ordinary Portland Cement shall conform to IS: 269, Portland Blast Furnace Slag Cement shall conform to IS: 455. Use of Portland Pozzolana Cement shall be only with prior approval of the MMCI/HPCL Engineer-in-Charge.

3.2

Aggregates Aggregates in general designate both fine and coarse inert materials used in the manufacture of concrete. The fine aggregate is aggregate which passes through 4.75 mm IS Sieve. Coarse aggregate is aggregate most of which is retained on 4.75 mm IS Sieve. All aggregates shall conform to IS: 383. Fine aggregate shall consist of natural sand, i.e. river or pit sand. Coarse aggregate shall consist of crushed gravel, natural gravel, crushed stone or combination thereof conforming to requirements of grading and physical properties called for. However, bank run gravel shall not be permitted for coarse aggregates. The fineness modules of sand should be between 2.2 to 3.2 for concrete works. The maximum size of coarse aggregate shall be 38 mm except for slabs and walls less than 250 mm thick which shall have a maximum size of 19 mm. Blast furnace slag and manufactured sand shall not be used as aggregates.

3.3

Water Water used for both mixing and curing shall be free from injurious amounts of deleterious materials and shall be of potable quality conforming IS: 456.

3.4

Brick Aggregates The brickbats shall be new bricks well burnt, hard durables, broken to sizes and well graded. It shall be free from dust, earth and any other impurities.


VISAKH MARKETING INSTALLATION REISTEMENT PROJECT-BLACK OIL TERMINAL Doc No: 254625-300-SP-CIV-002 3.5

Rev: B

Page 8 of 24

Reinforcement Reinforcement shall be of tested quality M.S. round rods conforming to IS:432, IRC wire mesh fabric conforming to IS:1566, mild steel and medium tensile steel deformed bars conforming to IS:1139 and cold twisted steel bars conforming to IS:1786 as shown in drawings. All reinforcement shall be clean, free from grease, oil, paint, loose mill scale, loose rust, dust, bituminous material or any other material or substance that will destroy or reduce the bond. 16 SWG (1.6 mm) approved soft annealed steel wire shall be used for binding the reinforcement bars.

3.6

Water Stoppers Metallic water stopper shall be fabricated from 22 gauge G.I. sheet of specified width and bent, folded to shape, soldered and fixed. The transverse joints of the sheets shall either be welded, brazed or overlapped. In case of overlapping of the stoppers the minimum overlap should be equal to width of such water stopper. PVC and rubber water stops shall be either ribbed or serrated type having a minimum thickness of 6 mm. These can be of approved make, such as "PASK", "CALICO" or approved equivalent. They shall be accurately cut, fitted and integrally joined as per manufacturer's specifications.

3.7

Jointing/Sealing Materials All joint fillers, sealing materials etc. used for joints in concrete shall be from approved standard manufacturer and shall conform to relevant IS codes. The extent, type, method of use and control shall be as per manufacturer's recommendation, subject to approval of the MMCI/HPCL Engineer-in-Charge.

3.8

Admixtures Admixtures shall be used strictly in accordance with the manufacturer's instructions and shall conform to the relevant IS codes (for eg. IS: 9103). Vendor's instruction shall be successfully incorporated in the trial mix. The extent, type, method of use and control shall be subject to approval of the MMCI/HPCL Engineer-in-Charge in all cases. Integral water proofing compound shall conform to IS: 2645.

4

Storage of Materials

4.1

Cement Cement shall be stored in a damp-proof hopper or in sealed bags in a weather proof shed, on a floor above ground and shall be used in the order of its delivery. Different types or brands of cement shall be stored separately. Not more than 12 bags shall be stacked in any tier.

4.2

Aggregates Aggregates of different sizes shall be kept separately. Aggregates of similar grading but from different sources or different types shall not be stored together unless approved. All aggregates shall be stored in such a way that they are free from contact of deleterious matter.



4.3

Rev: B

Page 9 of 24

Reinforcing Steel Reinforcing steel members and wire mesh which are stored at the project site shall be above ground on platforms, skids or other supports. Steel shall be protected from rain, moisture and kept free from dirt, oil or contaminant injuries.

4.4

Miscellaneous All other materials shall be stored in a weather tight and dry place and be protected from open flame or sparks. All packed materials shall be stored in their original unbroken package or container.

5

Grades of Concrete Unless otherwise noted on the drawings, or called for in the schedule of rates, the grades of concrete shall generally be as per Table-1. TABLE - 1 GRADES OF CONCRETE Grade Designation

Specified Characteristic Compressive Strength of 150 mm 2

M 7.5

7.5

M 10

10

M 15

15

M 20

20

M 25

25

M 30

30

M 35

35

M 40

40

M 45

45

M 50

50

M 55

55

Note for Table - 1 : The characteristic strength is defined as the strength of material below which not more than five (5) percent of the test results are expected to fall. In the designation of concrete mix the letter ‘M’ refers to the mix and the number to the specified characteristic compressive strength of 15 cm cube at 28 days expressed in N/sq. mm. P:\Andheri\IndiaProject\254625 HPCL- Black Oil Terminal\02 Civil\Documents\Deliverables\Documents\Latest\SPECIFICATIONS\REV B\Spec for Plain and Reinforced Cement Concrete.doc

VISAKH MARKETING INSTALLATION REISTEMENT PROJECT-BLACK OIL TERMINAL Doc No: 254625-300-SP-CIV-002 6

Type of Concrete Mix

6.1

General

Rev: B

Page 10 of 24

Unless otherwise noted on drawings, all lean/plain and reinforced concrete shall be nominal mix and design mix types, respectively. 6.2

Nominal Mix Concrete This concrete shall be made (without preliminary tests) by adopting nominal concrete mix with proportions of materials as specified in Table-1 A TABLE - 1A PROPORTIONS FOR NOMTNAT. MIX CONCRETE Quantity of water per 50 kg of cement Nominal mix of concrete (by mass) (max) Litres 1:5:10 60 1:3:6 34 M 15(1:2:4) 32 M 20(l:1l/2:3) 34 Note: 1. The proportions of the fine to coarse aggregates should be adjusted from upper limit to lower limit progressively as the grading of the fine aggregates becomes finer and the maximum size of coarse aggregates becomes larger. Graded coarse aggregates shall be used. 2. The cement content of the mix shall be proportionately increased if the quantity of water in a mix has to be increased to overcome the difficulties of placement and compaction, so that the water-cement ratio, as specified, is not exceeded.

6.3

Design Mix Concrete The mix shall be designed to produce the grade of concrete having the required workability and characteristic strength not less than appropriate values given in Table-1. The target mean strength of concrete mix shall be equal to the characteristic strength plus 1.65 times the standard deviation. As long as the quality of materials does not change, a mix design done earlier may be considered adequate for later work. However, in case the quality of materials changes or there is a break in the continuity of construction and the same work is allocated to a new contractor, the MMCI/HPCL Engineer-in-Charge shall ask for a new design mix. Irrespective of the grade of concrete required to be produced as per characteristic. The strength criteria, the minimum cement content and maximum free water cement ratio in the design concrete shall be strictly maintained as stipulated in Table 2A for the corresponding grade of concrete. The contractor at his own cost; grade the aggregates and control the water/cement ratio, design & conduct the different trial mixes to required strength and workability & obtain Engineer-in charge’s approval for the same. Duly approved mixes in accordance with IS: 456 shall be used for construction.



Rev: B

Page 11 of 24

All concrete shall be machine mixed and no hand mixing shall be permitted. The concrete shall continuously agitate from mixing to pouring. The use of non agitating equipment in transporting ready mixed concrete or the use of partially hardened concrete is not allowed. Where reinforcement is too closely spaced for the maximum size of aggregate in a range, the largest suitable range will be used with the approval of the MMCI/HPCL Engineer-in-Charge. 7

Concrete Mix Proportioning Proportioning, as used in this specification, shall mean the process of determining the proportions of the various ingredients to be used to produce concrete of the required workability when fresh/green and strength, durability and surface finish, when hardened. The following information shall be collected prior to design of the concrete mix : a)

Grade designation

b)

Type of cement

c)

Maximum nominal size of aggregate

d)

Minimum cement content

e)

Maximum free water cement ratio

f)

Workability requirements.

The MMCI/HPCL Engineer-in-Charge shall verify the strength of the concrete mix, before giving his sanction of its use. However, this does not absolve the Contractor of his responsibility as regards achieving the prescribed strength of the mix. If during the execution of the work, cube tests show lower strengths than required, the MMCI/HPCL Engineer-inCharge shall order fresh trial mixes to be made by the Contractor. No claim to alter the rates of concrete work shall be entertained due to such changes in mix variations. Any variation in cement consumption shall be taken into consideration for material reconciliation. Preliminary mix designs shall be established well ahead of start of work. 7.1

Maximum Density Suitable proportions of sand and the different sizes of coarse aggregates for each grade of concrete shall be selected to give as nearly as practicable the maximum density. This shall be determined by mathematical means, laboratory tests, field trials and suitable changes in aggregate gradation. The contractor shall submit to the MMCI/HPCL Engineer-in-Charge at least three sets of mix design and corresponding test results after varying the mix proportions and / or grading of aggregate so as to establish the maximum density of any particular grade of concrete.

7.2

Free Water Cement Ratio Once a mix, including its free water cement ratio, has been determined and approved for use by the Engineer-in- Charge, that free water cement ratio shall be maintained. The Contractor shall determine the water content of the aggregates frequently as the work progresses, and the amount of mixing water shall be adjusted so as to maintain the approved free water cement ratio.



Rev: B

Page 12 of 24

Consistency The concrete shall have a consistency such that it shall be workable in the required position and when properly vibrated it flows around reinforcing steel, all embedded fixtures, etc. The consistency of concrete shall have to be controlled as per IS: 456 and the slump tests shall be carried out by the contractor in accordance with IS: 1199.

7.4

Workability

7.4.1

The concrete mix proportion shall be such that the concrete is of adequate workability for the placing condition and can be properly compacted with the means available. Use of additives of approved make shall be taken recourse to where required for attaining proper workability as specified under Cl. 7.4.2.

7.4.2

The suggested ranges of values of workability of concrete measured in accordance with IS:1199 are indicated in Table-2 below. However, the actual values to be followed shall be established depending on aggregate sizing, mix proportions, placing conditions, etc and shall be got approved by the MMCI/HPCL Engineer-in-Charge. At least one slump test shall be carried out per every compressive test performed. More frequent tests shall be made if there is a distinct change in work conditions, if required by MMCI/HPCL Engineer-in-Charge.

Placing conditions

Slump (mm)

Lightly reinforced sections in slabs, beams, walls, columns, footings and pavements

Low

25-75

Heavily reinforced sections in slabs, beams, walls, columns, slip- form work and pumped concrete.

Medium

50-100

High

100-150

Very High

150-200

In-situ piling Tremie concrete 7.5

TABLE - 2 Values of Workability Degree of workability

Durability For achieving sufficiently durable concrete, strong, dense aggregates, low water-cement ratio and adequate cement content shall always be used. Workability of concrete shall be such that concrete can be completely compacted with the means available. Leak-proof formwork shall be used so as to ensure no loss of cement-slurry during pouring and compaction. Cover to reinforcement shall be uniform and as shown on drawings. Concrete mix design shall always take into account the type of cement, minimum cement content irrespective of the type of cement and maximum free water cement ratio and minimum grade of concrete conforming to the exposure conditions as given in Table-2A.



Rev: B

Page 13 of 24

TABLE -2A Minimum Cement Content, Maximum Free Water Cement Ratio and Minimum Grade of Concrete for Different Exposure Conditions Plain Concrete Exposure

Mild Moderate Severe Very Severe Extreme

Minimum Cement Content (kg/m3) 240 265 275 280 310

Reinforced Concrete

Maximum Minimum Maximum Free Minimum Minimum Cement Free Water Water Grade of Grade of Content Cement Cement Concrete Concrete (kg/m3) Ratio Ratio 0.6 0.6 0.5 0.45 0.4

M 15 M 15 M 20 M 20 M 20

330 330 350 375 400

0.55 0.50 0.45 0.45 0.4

M 20 M 25 M 30 M 35 M 40

Generally, the following types of cement shall be used for Plain and Reinforced concrete works: a)

33 Grade Ordinary Portland Cement conforming to IS: 269.

b)

43 Grade Ordinary Portland Cement conforming to IS: 8112: 1989

c)

Portland Slag Cement conforming to IS:455.

d)

Portland Pozzolana Cement conforming to IS: 1489.

e)

Sulphate Resisting Portland Cement conforming to IS: 12330: 1988

Sulphate Resisting Portland Cement shall be used only for specific requirements depending on environmental and process exposure conditions to which the structures may be subjected to like high sulphate concentrations, processes involving sulphur handling etc. The minimum cement content as mentioned in Table-2A shall be adjusted for aggregates other than 20mm nominal maximum size. The minimum cement content in the concrete mix shall be increased by 40kg/m3 and decreased by 30 kg/m3 for 10mm and 40mm nominal maximum size aggregates respectively. 8

Batching

8.1

In proportioning concrete, the quantity of both cement and aggregate shall be determined by mass. Where the mass of cement is determined on the basis of mass of cement per bag, a reasonable number of bags shall be weighed periodically to check the net mass. Where the cement is weighed at site and not in bags, it shall be weighed separately from the aggregates. Water shall be either measured by volume in calibrated tanks or weighed. Any solid admixtures that are to be added, shall be measured by mass; liquid and paste admixtures shall be measured by volume or mass. Batching plant, shall conform to IS:4925: 2004 All measuring equipment shall be maintained in a clean serviceable condition, and their accuracy shall be within 2% and 3%for measurement of cement and aggregates/water/admixtures, respectively.



Rev: B

Page 14 of 24

8.2

Under very special circumstances change from weigh batching to appropriate volume batching may be permitted by MMCI/HPCL Engineer-in-Charge. However, in such cases all conversions from mass of ingredients to volume shall be based on actual and appropriate bulk densities physically measured at site and approved by the MMCI/HPCL Engineer-in-Charge.

8.3

No substitutions in materials used on the work or alterations in the established proportions, except as permitted in 7.4 shall be made without additional tests to show that the quality and strength of concrete are satisfactory. In case the Contractor proposes any change in the already approved mix design, fresh mix design with supportive laboratory tests shall be submitted to the MMCI/HPCL Engineer-in-Charge and his approval has to be obtained prior to using the revised mix proportion in the works. However, such proposals for revision shall only be entertained in case of successive failure of test cubes to achieve the required strength.

9

Concrete Mixing

9.1

General The mixing of concrete shall be strictly carried out in an approved type of mechanical concrete mixer. The mixer shall be fitted with water measuring devices. The mixing shall be continued until there is a uniform distribution of the material and the mass is uniform in colour and consistency. If there is segregation after unloading from the mixer, the concrete shall be remixed. Use of Ready Mixed Concrete supplied by Ready Mixed Concrete Plants or from on/off-site batching plants (IS: 4926) shall be preferred for structural concrete. All records and charts for the batching and mixing operations shall be prepared and maintained by the contractor as per the instructions of MMCI/HPCL Engineer-in-Charge. Mechanical Mixers shall comply with IS: 1791 and 12119: 2004 and shall be maintained in satisfactory operating condition. Hand mixing of concrete shall not be permitted. However, for non-critical applications namely foundations for crossovers, isolated operating platforms etc. using concrete of maximum grade M20 and located at far away isolated places, this may be permitted by the MMCI/HPCL Engineer-in-Charge as a special case.

9.2

Additives Additive in concrete shall be used only with the prior approval of the MMCI/HPCL Engineerin-Charge and shall comply with IS: 456. Any additive used for obtaining proper workability or leak-proofness of concrete or repair/rendering works of concrete due to non-conformance to the specifications, shall not be measured and paid for. All costs relating to such usage shall be borne by the Contractor.

10

Transportation, Placing and Compaction

10.1

General The entire concrete placing programme including transportation arrangements, deployment of equipment, layout, proposed procedures and methods, shall be submitted to the MMCI/HPCL Engineer-in-Charge 24 hours prior to concreting for approval. No concreting shall be placed until his approval has been received. Approval of the MMCI/HPCL Engineer-in-Charge for pouring concrete shall be taken as 'conveyed', when the concrete pour card is signed by him.


VISAKH MARKETING INSTALLATION REISTEMENT PROJECT-BLACK OIL TERMINAL Doc No: 254625-300-SP-CIV-002 10.1.1

Rev: B

Page 15 of 24

Vibrators

10.1.1.1 In placing concrete in layers which are advancing horizontally as the work progresses, great care shall be exercised to ensure adequate vibration, bonding and moulding of the concrete between the succeeding batches. 10.1.1.2 The vibrator shall penetrate the layer being placed and also penetrate the layer below while the under layer is still plastic to ensure good bond and homogeneity between the two layers and prevent the formation of cold joints. 10.1.1.3 Care shall be taken to prevent contact of vibrators against all embedded reinforcing steel or inserts. Vibrators shall not be allowed to come in contact with forms. 10.1.2

Transportation

10.1.2.1 All concrete shall be conveyed from the mixer to the place of final deposit such as formwork as early as possible using suitable buckets, dumpers, pumps, transit mixers containers or conveyors which shall be mortar leak tight. Care shall be taken to prevent the segregation or loss of the ingredients and maintaining the required workability. For structural concrete produced from Ready Mixed Concrete Plants as per Cl. 9.1, concrete shall be transported from the plants to the sites only by transit mixers. 10.1.3

Placing and Compaction

10.1.3.1 Before placing concrete, all soil surfaces upon which or against which concrete is to be placed shall be well compacted and free from standing water, mud or debris. Soft or yielding soil shall be removed and replaced, with lean concrete or with selected soils/sand and compacted to the density as directed by MMCI/HPCL Engineer-in-Charge. The surface of absorptive soil (against which concrete is to be placed) shall be moistened thoroughly so that moisture is not drawn from the freshly placed concrete. Similarly, for concrete to be placed on formworks, all chippings, shavings and sawdust etc. shall be removed from the interior of the forms before the concrete is placed. Concrete shall be placed within a maximum period of 25 minutes of its removal from mixture. 10.1.3.2 Concrete shall not be placed until the formwork, the placement of reinforcing steel, embedded parts, pockets etc. have been inspected and approved by the Engineer- in-Charge. Any accumulated water on the surface of the bedding layer shall be removed by suitable means before start of placement. No concrete shall be placed on a water covered surface. 10.1.4

Items Embedded in Concrete

10.1.4.1 Concreting shall not be started unless the electrical conduits, pipes, fixtures etc., wherever required, are laid by the concerned agency. The Contractor shall afford all the facilities and maintain co-ordination of work with other agencies engaged in electrical and such other works as directed by the MMCI/HPCL Engineer-in-Charge. 10.1.4.2 Before concreting, the Contractor shall provide, fabricate and lay in proper position all metal inserts, anchor bolts, pipes etc. (which are required to be embedded in concrete members) as per relevant drawings and directions of MMCI/HPCL Engineer-in-Charge. 10.1.4.3 Anchor bolts shall be set to template and firmly tied/fixed in vertical & horizontal line at all required positions. P:\Andheri\IndiaProject\254625 HPCL- Black Oil Terminal\02 Civil\Documents\Deliverables\Documents\Latest\SPECIFICATIONS\REV B\Spec for Plain and Reinforced Cement Concrete.doc


Rev: B

Page 16 of 24

10.1.4.4 All embedment, inserts etc. shall be fully held and secured in their respective positions by the concerned agencies to the entire satisfaction of MMCI/HPCL Engineer-in-Charge so as to avoid any dislocation or displacement during the concreting operations. The Contractor shall take all possible care during concreting to maintain these embedment/inserts in their exact locations. 11

Construction Joints

11.1

Construction joints shall be provided in position as shown or described on the drawings or as directed by the MMCI/HPCL Engineer-in-Charge. Such joints shall be kept to the minimum. These shall be straight and at right angles to the direction of main reinforcement and shall be placed at accessible locations to permit cleaning out of laitance, cement slurry and unsound concrete.

11.2

In a column, the joint shall be formed about 100mm to 150mm below the lowest soffit of the beams framing into it. Concrete in a beam and slab shall be placed throughout without a joint but if the provision of a joint is unavoidable, the joint shall be vertical and located within 1/3 to 1/4 of the span, unless otherwise shown on the drawings.

11.3

When stopping the concrete on a vertical plane in slabs and beams, an approved stop board shall be placed with necessary slots for reinforcement bars. The construction joints shall be keyed by providing a triangular or trapezoidal fillet nailed on the stop board. Inclined joints shall not be permitted. Any concrete flowing through the joints of stop board shall be removed soon after the initial set. When concrete is stopped on a horizontal plane, the surface shall be roughened and cleaned after the initial set and a triangular or trapezoidal groove shall be provided for keying with the new concrete later.

12

Expansion Joints / Isolation Joint

12.1

Expansion/ Isolation joints in structures shall be formed in the positions and to the shapes shown in the relevant drawings. Joints shall be filled with joint filling material as stipulated in the drawings/schedule of rates. Isolation joints shall be provided around all equipment foundations, columns, pedestals, trenches etc. on grade.

13

Protection of Freshly Laid Concrete

13.1

Newly placed concrete shall be protected, by approved means, from rain, sun and wind. Concrete placed below the ground level shall be protected from falling earth during and after placing. Surface shall be kept free from contact with such ground or with water draining from such ground during placing of concrete for a period of at least 3 days, unless otherwise directed by the MMCI/HPCL Engineer-in-Charge. The ground water around newly poured concrete shall be kept to an approved level by pumping or other approved means of drainage and adequate steps shall be taken to prevent floatation and flooding. Steps shall be taken to protect immature concrete from damage by debris, loading, vibration, abrasion, mixing with deleterious materials that may, in the opinion of the MMCI/HPCL Engineer-in-Charge, impair the strength and/or durability of the concrete.

14

Curing

14.1

Concrete shall be cured by keeping it continuously moist wet for the specified period of time to ensure complete hydration of cement and its hardening. Curing shall be started after 8 hours



Rev: B

Page 17 of 24

of placement of concrete in normal weather, and in hot weather after 4 hours. The water used for curing shall be of the same quality as that used for making of concrete. Curing shall be assured by use of an ample water supply under pressure in pipes, with all necessary appliances such as hose, sprinklers etc. A layer of sacking, canvas, hessian, or other approved material, which will hold moisture for long periods and prevent loss of moisture from the concrete, shall be used as covering. Type of covering which would stain, disfigure or damage the concrete, during and after the curing period, shall not be used. Only approved covering shall be used for curing. Exposed surfaces of concrete shall be maintained continuously in a damp or wet condition for at least the first 7 days after placing of concrete. 14.2

For concretes containing Portland pozzolana cement or Portland slag cement, the curing period as given in 16.1 shall be doubled. Curing by ponding shall, however, commence after the first 24 hours of concreting.

15

Field Tests

15.1

Workability

15.2.1

The concrete mix proportion so chosen, shall be such that the concrete is of adequate workability for the placing condition and can be property compacted with the means available.

15.2.2

The suggested ranges of values of workability of concrete measured in accordance with IS: 1199 are indicated in Table-5. TABLE -5 Placing Conditions

Degree of Workability

Concreting of shallow section with vibration

Very Low

20-10 seconds, Vee Bee time or 0.75 - 0.80, Compacting factor

Low

10-5 seconds, Vee Bee time or 0.8 - 0.85, Compacting factor

Concreting of lightly reinforced sections with vibration Concreting of lightly reinforced sections without vibration, or Heavily reinforced sections with vibrations Concreting of heavily reinforced sections without vibrations

Medium

High

Value of Workability

5-2 seconds, Vee Bee time or 0.85 - 0.92, Compacting factor or 25-75 mm, slump for 20 mm aggregate above 0.92, Compacting factor or 75-125 mm, slump for 20 mm* aggregate



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* For smaller aggregate the values will be lower. 15.2

Work Tests

15.2.1

Over the full period of construction, the contractor shall carry out work tests of concrete at his own cost. Sampling from fresh concrete shall be taken as per IS: 1199 and cubes shall be made, cured and tested in accordance with IS: 516. The number of specimen to be tested and their criteria for acceptance shall be according to IS: 456. Frequency of work tests shall be as indicated below:

15.2.2

Frequency of Tests

15.2.2.1 Unless otherwise specified, for each grade of concrete, sets of test cube, each set consisting of three (3) twin specimens (i.e. total 6 Nos.) shall be taken. Number of sets shall generally be calculated based on the types and corresponding volumes of work as indicated hereunder unless otherwise directed by the MMCI/HPCL Engineer-in-Charge. Mass Concrete Foundations

:

For every 100 Cu. M of concrete placed, one set but not less than one set for each pouring of concrete

Equipment and building Column : foundations :

For every 50 Cu. m of concrete placed one set but not less than one set for each pouring of concrete

Frame & thin walled Structural : components Columns, beams, slabs etc.

For every 30 Cu. m of concrete placed one set but not less than one set for each pouring of concrete

15.2.2.2 The test cubes shall be sampled in presence of the MMCI/HPCL Engineer-in-Charge./Owner's representative, who will also sign the record of testing in an agreed format. 15.2.2.3 For testing the cube specimen contractor shall establish his own construction laboratory at site and the cost of testing of cubes shall be borne by him. 15.2.2.4 Supply of all required consumables, construction and erection materials including but not limited to gauges, welding, brazing, gasses and rods, electrodes, oxygen, acetylene, fuel, bolts, nuts and temporary support etc. shall be by contractor at no extra cost. 15.3

Standard Deviation Standard deviation shall be calculated as given in IS: 456.

15.4

Acceptance Criteria

15.4.1

The concrete shall deemed to be accepted if it fulfils the requirements laid down in IS: 456.

15.4.2

lf the concrete does not comply with IS: 456, the structural adequacy of the parts affected shall be investigated and any consequential action as needed shall be taken up by the contractor at his own cost. Concrete of each grade shall be assessed separately. Concrete shall be assessed daily for compliance. Concrete is liable to be rejected if it is porous or honey-combed; its placing has been interrupted without providing a proper construction joint; the reinforcement has been displaced beyond the tolerances specified; or construction tolerances have not been



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met. However, the hardened concrete may be accepted after carrying out suitable remedial measures to the satisfaction of the MMCI/HPCL Engineer-in-Charge. 16

Finishing of Concrete

16.1

General On striking the formwork, all surface defects such as bulges, ridges and honey-combing etc. observed shall be brought to the notice of the MMCI/HPCL Engineer-in-Charge. The MMCI/HPCL Engineer-in-Charge may, at his discretion allow rectification by necessary chipping and packing or grouting with concrete or cement mortar. However, if honeycombing or sagging are of such extent as being undesirable, the MMCI/HPCL Engineer-inCharge may reject the work totally and his decision shall be binding. No extra payment shall be made for rectifying these defects, demolishing and reconstructing the structure. However, quantity of cement actually used for this purpose may be considered for reconciliation of materials. All burrs and uneven faces shall be rubbed smooth with the help of carborundum stone. The surface of non-shuttered faces shall be smoothened with a wooden float to give a finish similar to that of the rubbed down shuttered faces. Concealed concrete faces shall be left as from the formwork except that honey-combed surface shall be made good as specified above. The top faces of slabs not intended to be covered shall be levelled and floated to a smooth finish to the rises or falls shown on the drawings or as directed. The floating shall not be executed to the extent of bringing excess fine materials to the surface. The top faces of slabs intended to be covered with screed, granolithic or similar finishes, shall be left with a rough finish.

17

Form Work

17.1

General

17.1.1

Forms for concrete shall be of plywood conforming to IS: 6461 or steel or as directed by the MMCI/HPCL Engineer-in-Charge and shall give smooth and even surface after removal thereof.

17.1.2

If it is desired by the MMCI/HPCL Engineer-in-Charge, the Contractor shall prepare, before commencement of actual work, design and drawings for formwork and get them approved by the MMCI/HPCL Engineer-in-Charge. For details regarding design, detailing etc., reference may be made to IS: 14687.

17.2

Cleaning and Treatment of Formwork The surfaces of forms that would come in contact with concrete shall be well treated with approved non- staining form release agents such as soft soap, oil, emulsions etc. Release agents shall be, applied so as to provide a thin uniform coating to the forms without contaminating the reinforcement.

17.3

Chamfers and Fillets All corners and angles shall be formed with 45 degree mouldings to form chamfers or fillets on the finished concrete. The standard dimensions of chamfers and fillets, unless otherwise detailed or specified shall be 25x25mm. For heavier work chamfers or fillets shall be 50x50mm. Care shall be exercised to ensure accurate mouldings. The diagonal face of the moulding shall be planed or surfaced to the same texture as the forms to which it is attached.



17.4

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Page 20 of 24

Reuse of forms Before reuse, all forms shall be thoroughly scrapped, cleaned, examined and when necessary, repaired and retreated, before resetting. Formwork shall not be reused, if declared unfit or unserviceable by the MMCI/HPCL Engineer-in-Charge.

17.5

Removal of Forms/Stripping Time In the determination of time for removal of forms, consideration shall be given to the location and character of the structures, the weather and other conditions including the setting and curing of the concrete and material used in the mix. Forms and their supports shall not be removed without the approval of the MMCI/HPCL Engineer-in-Charge. Forms shall not be released until the concrete has achieved a strength of at least twice the stress to which the concrete may be subjected at the time of removal. The formwork shall be removed without shock and methods of form removal likely to cause over stressing' or damage to the concrete, shall not be adopted. Supports shall be removed in such a manner as to permit the concrete to uniformly and gradually take the stresses due to its own weight. In normal circumstances when average air temperature exceeds 15 degree Celsius during the period under consideration after pouring of concrete and where ordinary Portland cement is used, forms may generally be removed after expiry of following periods. (a)

Walls, columns and vertical faces of all structural members

16 to 24 hours as may be decided by the MMCI/HPCL Engineer-in-Charge.

(b)

Slabs (props left under)

3 days

(c)

Beam Soffits (props left under)

7 days

(d)

Removal of props under slabs:

(e)

(f)

Spanning upto 4.5m.

7 days

Spanning over 4.5m

14 days

Removal of props under beams and arches: Spanning upto 6m

14 days

Spanning over 6m

21 days

Cantilever Construction

Formwork shall remain till structures for counter acting or bearing down have been erected and have attained sufficient strength (minimum 14 days).

Notes: 1. For other cements, the stripping time recommended for ordinary Portland cement shall be suitably modified as per the instructions of the Engineer- in-Charge. P:\Andheri\IndiaProject\254625 HPCL- Black Oil Terminal\02 Civil\Documents\Deliverables\Documents\Latest\SPECIFICATIONS\REV B\Spec for Plain and Reinforced Cement Concrete.doc


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2.

The number of props left under, their sizes, supporting arrangement, and disposition shall be such as to be able to safely carry the full dead load of the slab, beam or arch as the case may be together with any live load likely to occur during curing or further construction.

3.

Where the shape of the element is such that the formwork has re-entrant angles, the form work shall be removed as soon as possible after the concrete has set, to avoid shrinkage cracking occurring due to the restraint imposed.

4.

For rapid hardening cement, 3/7 of the above mentioned periods shall be considered subject to a minimum of 16 hours.

18

Exposed / Architectural Concrete Work

18.1

Form Work Other things remaining same as per clause 20.0, formwork shall be of high quality. Care shall be taken to arrange the forms so that the joints between forms correspond with the pattern indicated in the drawings. The forms shall be butting with each other in straight lines, the corners of the boards being truly at right angles. The joints between the forms shall cross in the two directions at right angles. The size of forms shall be so selected as to exactly match with the pattern of forms impression on the concrete face indicated in the drawings. Maximum care shall be taken to make the form work watertight. Burnt oil shall not be used for treatment of forms. The Contractor shall be permitted reuse of forms brought new on the work for exposed concrete work as specified below.

19

Reinforcement The Contractor shall develop the bar bending schedule for all RCC structures/ structural parts at no extra cost to the Owner and shall get it reviewed by the MMCI/HPCL Engineer-inCharge. Reinforcement shall be cut and bent to shape as per dimensions shown in the bar bending schedule/ drawings.

19.1

Straightening, Cutting and Bending Procedure for cutting and bending shall be as given in IS: 2502. In case bars are supplied in coils, they shall be smoothly straightened without any kinks.

19.2

Placing and Fixing All reinforcement shall be cleaned to ensure freedom from loose mill scale, loose rust, oil, form releasing agents, grease or any other harmful material before placing them in position. Reinforcement shall not be surrounded by concrete unless it is free from all such materials. Rough handling, and dropping of reinforcement from a height shall be avoided All reinforcement shall be fixed in the correct position and shall be properly supported to ensure that displacement will not occur when the concrete is placed and compacted. The uncoated reinforcement bars shall be tied at every intersections by two strands of 16 SWG black soft annealed binding wire. Crossing bars shall not be tack welded for assembly of reinforcement.



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Page 22 of 24

Splicing/Overlapping Only bars of full length shall be used as shown in the drawings. But where this cannot be done, overlapping of bars shall be done as directed by the Engineer-in- Charge. Where practicable, the overlapping bars shall not touch each other, but these shall be kept apart by 25mm or 1.25 times the maximum size of the coarse aggregate whichever is greater. But where this is not possible, the overlapping bars shall be tied with two strands of 16 SWG black soft annealed binding wire for uncoated bars GI 18 SWG wire. The overlaps shall be staggered for different bars and located at points along the span where neither shear nor bending moment is maximum.

19.4

Tolerance to Cover The actual concrete cover shall not deviate from the required nominal cover by - 0 to + 10 mm measured over the steel reinforcement including links.

20

Damp Proof Course (DPC)

20.1

The 14 mm thick damp proof course shall consists of plain cement concrete of grade M 15 or nominal mix concrete of 1:2:4 (1 cement: 2 coarse sand : 4 stone aggregate) with 10 mm and down graded aggregate, unless otherwise specified.

20.2

The DPC shall be laid at plinth level of brick walls, flush with the floor surface and shall not be carried across doorways.

20.3

Before laying the top surface of wall shall be thoroughly cleaned and watered. The DPC shall be laid in layers of 20 mm thickness retaining the edges by necessary formwork and shall be well tamped and trowelled to smooth finish. DPC should be kept wet for at least 3 days and after it has dried, two coats of hot bitumen of grade A 90 / S 90 conforming to IS: 73 shall be applied over it at the rate of 1.7 kg / sq. m. and over this dry sand shall be sprinkled evenly.

21

Grouting

20.1

Before placing the grout, the concrete surface shall be thoroughly cleaned, preferably with compressed air and the surface shall be thoroughly wetted with water for several hours. Grouting concrete shall be of grade M20 or more unless otherwise shown in the drawing with 6 mm down stone aggregates. Before placing the grout all free water shall be removed and the flat surface shall be coated with thin cement slurry. The grout shall be carefully observed for initial settlement. If any settlement is observed, further grout is to be poured and compacted by rods. For base plates having ribs underside the base plate, proper care is to be taken to ensure filling of the cavities between the ribs. In case of wide base plates or bed plates having ribs underside, it may be necessary to do pressure grouting as directed by the MMCI/HPCL Engineer-in-Charge.

20.2

Graving The grout must not dry out after it is placed in position. The surface shall be kept moist with wet sacks for at least seven days.

20.3

Admixtures



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Page 23 of 24

If any admixtures is to be used with the grout, it shall be with prior approval of the MMCI/HPCL Engineer-in-Charge. 20.3.1

Non-Shrinking Grout Non shrinking grout where required shall be used in accordance with the methods specified by the manufacturer. Material shall be as approved by the MMCI/HPCL Engineer-in-Charge.

20.3.2

The placement of grout shall be continuous so as to avoid "cold joints" under base plate and thoroughly worked under so as to eliminate air bubbles and voids. Rods or chains may be used to expedite this procedure. Grout shall be placed so as to provide full and uniform bearing under all bearing surfaces. Where forms are used for grouting, they shall remain in place for a period of 24 hours unless directed otherwise. All exposed grout with a thickness of 25 mm or more shall be sloped at about 45 degree unless otherwise noted.

22

Clean Up Upon the completion of concrete work, all debris, scraps of wood etc. resulting from the work shall be removed and the premises left clean.

23

Payment

23.1

Plain and Reinforced Concrete

22.1.1

Payment for plain and reinforced cement concrete (cast- in-situ) shall be made on cubic metre basis of the volume of the actual finished work done or as per approved construction drawings, whichever is less and shall be inclusive of providing pockets, openings, recesses of all sizes, chamfers, fillets, grooves, separation/ expansion/ isolation/ construction/ movement joints, cement wash, curing by normal moist curing or using curing compound etc. as directed by MMCI/HPCL Engineer-in-Charge etc. The rates shall be deemed to include complete cost of getting the respective mix designs approved, making and testing concrete cubes and carrying out other tests including tests of various ingredients, as per specifications and as directed by MMCI/HPCL Engineer-in-Charge. Payment shall, however, be separately made for tests on concrete cubes done by accelerated methods of curing as defined in IS: 9013.

22.1.2

No separate payment shall be made for any additive/ admixture used by the contractor for accelerating or retarding the strength of concrete or for achieving specified workability/water tightness. The rate quoted shall be deemed to be inclusive of all costs related to any such additive/ admixture.

22.1.3

The rate shall however be exclusive of reinforcement, metal inserts, pipe sleeves and any filler material in expansion/isolation joints.

22.1.4

Where the strength of concrete mix (nominal or design) as indicated by tests, lies in between the strengths of any two grades given in Table-1 and it is accepted by the Owner/MMCI/HPCL MMCI/HPCL Engineer-in-Charge, such concrete shall be classified as a grade belonging to the lower of the two grades between which it lies. In case the cube strength shows higher results than those specified for the particular grade of the concrete, it shall not be placed in the higher grade nor shall the Contractor be entitled for any extra payment on such account. The concrete giving lower strength than specified may be accepted at reduced rates after satisfying the safety of the structure by checking it with tests as specified or rejected entirely at the discretion of the Engineer-in- Charge. The rejected concrete shall be



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dismantled at no extra cost to the owner and no payment or extension of time shall be granted for the concrete so rejected and the formwork and reinforcement used for the same. Cost of any material supplied by the Owner free of cost shall be recovered from the Contractor at double the prevailing market rate. In case the concrete of lower strength can be improved by carrying out some strengthening measures entirely at the discretion of the MMCI/HPCL Engineer-in-Charge, then the said measures including all related tests shall be carried out by Contractor at his own cost. If the Contractor is able to make up the strength to the required grade by such improvement measures to the entire satisfaction of MMCI/HPCL Engineer-inCharge, payment shall be made for the grade achieved. However, if the strength of concrete is not made up to the strength of required grade, payment shall be made only for the lower strength if such concrete is accepted by the MMCI/HPCL Engineer-in-Charge. 22.1.5

Deductions for openings, pockets etc. shall be as specified in relevant Indian Standard Codes.

22.1.6

Payment under continuous concreting item in the schedule of rates shall be made only where the total quantity of concrete between two consecutive construction joints specifically calledout on the drawings exceeds 250 cubic metres. For any foundation/structure involving concrete quantity upto 250 cubic metres between two consecutive construction joints shown on drawings, the concrete shall not be measured or paid for under this category (i.e. continuous concreting), although the same is required to be constructed in single pour. The rate quoted against this item shall be inclusive of all extra costs incurred by the Contractor for arranging continuous pouring of concrete and others as specified complete.

23.2

Reinforcement

22.2.1

Payment for plain round mild steel reinforcement bars and high strength deformed steel bars shall be on the basis of weight of bare steel irrespective of any coating applied in metric tons. The weight of the bar shall be derived from the sizes and corresponding unit weights given in handbook of Bureau of Indian Standards. Standard hook lengths, chairs, spacer bars and authorised laps only shall be included in the weight calculated. Binding wire shall not be weighed nor otherwise measured. Measurements for weight shall not include cutting allowance etc.

22.2.2

Rate quoted for uncoated reinforcement shall include cost of supplying, decoiling, straightening, cleaning, cutting, bending, placing, binding, welding, if required, and providing necessary cover blocks of concrete.

22.2.3

Rate quoted for Fusion Bonded Epoxy Coated bars shall also include, apart from those mentioned in Cl. 27.3.2, cost of coating of the bars, all necessary tools and tackles and any repairs required due to damage to coating as per IS: 13620-1973.

22.2.4

Payment for mechanical threaded couplers shall be made on number basis (each). The rate shall include supply of complete assembly, fixing, testing etc. all complete.

23.3

Expansion/Isolation Joints

22.3.1

Payment for filler materials in Expansion/Isolation joints shall be made on running metre basis of the joint provided. For boards provided at expansion/isolation joints, the measurement shall be made on square metre basis. Rate shall be inclusive of supply, cutting, fixing, jointing, wastage etc. complete.
